Theresa May signs Brexit deal with EU leaders as her Cabinet plots to rip up her agreement

However, May's Cabinet are already preparing to rip up the deal when it is thrown out by the UK parliament when it returns to the UK in early December.

Some senior Cabinet ministers are pushing May to move decisively towards accepting a soft Brexit inside a permanent customs union with the EU.

Doing so could potentially draw the support of opposition MPs but would risk a major split within her own party.

The DUP threaten to withdraw their support from May's government if the deal is passsed by UK parliament.

LONDON — Theresa May faces a fresh rebellion from her Cabinet that could yet force her to rip up the deal she has just signed with EU leaders.

EU leaders agreed to the Brexit Withdrawal Agreement in Brussels at a special summit on Sunday.

Speaking at a press conference this afternoon Theresa May said she had agreed "the best possible deal" for the UK.

"It is the best deal available, the only possible deal," she said.

However, as May signed up Britain to the terms of the deal agreed in principle last week, members of her Cabinet at home threatened to force her to throw out the deal if and when it is rejected by the UK parliament.

With all opposition parties and up to 80 Conservative MPs pledged to oppose May's deal when it comes to the House of Commons, Remainer ministers in her Cabinet are pushing for the prime minister to seek an alternative deal that would leave Britain with a closer relationship with the EU after Brexit.

Five ministers, led by the Chancellor Philip Hammond are reportedly pushing for May to adopt a permanent customs partnership with the EU that could potentially draw the support of Labour MPs as well as the Democratic Unionist Party that has propped up her minority government.

Meanwhile the Democratic Unionist Party, which props up her minority government, threatened to withdraw their support for the Conservatives if the deal is agreed by the UK parliament.

Asked on Sunday if there were any circumstances in which her party would back May's deal in parliament, Foster told the BBC: "no there aren't."

She added that the DUP would "review" their agreement to prop up May's government if the deal were passed by Parliament.

"If [Parliament] did decide to back this deal we would have to decide to review the confidence and supply agreement," she said.

One senior Conservative told the Sunday Times that any attempt to force a hard no-deal Brexit would lead to a mass walkout from Cabinet: "If she said she'd go for mitigated no deal, she would lose most of her cabinet. And this time she wouldn't be losing Esther McVey and Dominic Raab, she'd be losing her most senior ministers. Hammond, Rudd, Lidington, Gauke and Clark would all resign."

Meanwhile, Cabinet Brexiteers, including the leader of the House Andrea Leadsom are also poised to quit if May moves any further towards accepting a closer relationship with the EU after Brexit.

Speaking on the BBC, the Foreign Secretary Jeremy Hunt acknowledged that May's deal "isn't perfect" and admitted that it would struggle to make its way through parliament and may even lead to the collapse of the government if it is voted down.

Asked whether the deal would leave Britain better off than remaining in the EU, he told the Andrew Marr programme that "We won't be significantly worse off or better off."

Labour leader Jeremy Corbyn said the party would oppose May's deal in parliament.

"This is a bad deal for the country. It is the result of a miserable failure of negotiation that leaves us with the worst of all worlds. It gives us less say over our future, and puts jobs and living standards at risk," he said in a statement.

"That is why Labour will oppose this deal in parliament. We will work with others to block a no deal outcome, and ensure that Labour's alternative plan for a sensible deal to bring the country together is on the table."

As the deal was signed multiple EU leaders warned that they bloc would not be prepared to renegotiate the deal.

European Commission President Jean-Claude Juncker told reporters that the EU would "not change its fundamental position" on Brexit, adding that this "is the best deal possible."

This position was backed by Dutch Prime Minister Mark Rutte.

This is the deal on the table," Rutte told reporters. "I don't think there is anything more … in general, this is the max we can all do, both Theresa May and her government as well as the EU."

In an open letter to the nation written ahead of today's summit, May promised to bring the country together with her deal.

"I want that to be a moment of renewal and reconciliation for our whole country," she writes.

"It must mark the point when we put aside the labels of 'leave' or 'remain' for good and we come together again as one people. To do that we need to get on with Brexit now by getting behind this deal. I will be campaigning with my heart and soul to win that vote."

Our Brexit Insider Facebook group is the best place for up-to-date news and analysis about Britain's departure from the EU, direct from Business Insider's political reporters. Join here.